/**
 * 字符串查找，因为规模极小，直接find即可
 */
#include <bits/stdc++.h>
using namespace std;
#include <bits/extc++.h>
using namespace __gnu_pbds;

using vi = vector<int>;
using pii = pair<int, int>;
using vpii = vector<pii>;

int N;
string S;
string T{"chuan"};

void work(){ 
    cin >> N >> S;
    int ans = 0;
    int k = 0;
    while(1){
        auto t = S.find(T, k);
        if(t == string::npos) break;

        ++ans;
        k = t + 1;
    }
    cout << ans << endl;
	return;
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("z.txt", "r", stdin);
#endif
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);	
    int nofkase = 1;
	// cin >> nofkase;
	while(nofkase--) work();
	return 0;
}